Tom Swift And His War Tank by Victor Appleton

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Then, at least for once, the man's suave manner droppedfrom him as if it had been a mask. He bared his teeth in asnarl as he answered:

"Mind your own business!"

"Something I'd advise you also to do," replied Nedsmoothly. "You can't see anything from there," he went on."Better go back to the tree and--cut a fishing pole!"

With this parting shot Ned sauntered down the hill, andswung around to make his way toward Tom's home. He paid nofurther attention to the man, save to determine, bylistening, that the fellow was searching among the bushesfor the dropped telescope.

The young inventor was at home, taking a hasty lunch whichMrs. Baggert had set out for him, the while he poured oversome blueprint drawings that, to Ned's unaccustomed eyes,looked like the mazes of some intricate puzzle.

"Well, where have you been keeping yourself, old man?"asked Tom Swift, after he had greeted his friend.

"I might ask the same of you," retorted Ned, with a smile."I've been trying to find you to give you some importantinformation, and I made up my mind, after what happened to-day, to write it and leave it for you if I didn't see you."

"What happened to-day?" asked Tom, and there was a seriouslook on his face.

"You are being spied upon--at least, that part of yourworks enclosed in the new fence is," replied Ned.

"You don't mean it!" Cried Tom. "This accounts for some ofit, then."

"For some of what?" asked Ned.

"For some of the actions of that Blakeson, He's beenhanging around here, I understand, asking too many questionsabout things that I'm trying to keep secret--even from mybest friends," and as Tom said this Ned fancied there was anote of regret in his voice.

"Yes, you are keeping some things secret, Tom," said Ned,determined "to take the bull by the horns," as it were.

"I'm sorry, but it has to be," went on Tom. "In a littlewhile

"Oh, don't think that I'm at all anxious to know things!"broke in Ned. "I was thinking of some one else, Tom--anotherof your friends."

"Do you mean Mary?"

Ned nodded.

"She feels rather keenly your lack of explanations," wenton the young bank clerk. "If you could only give her a hint

"I'm sorry, but it can't be done," and Tom spoke firmly."But you haven't told me all that happened. You say I ambeing spied upon."

"Yes," and Ned related what had taken place in the tree.

"Whew!" whistled Tom. "That's going some with a vengeance!I must have that tree down in a jiffy. I didn't imaginethere was a spot where the yard could be overlooked. But Ievidently skipped that tree. Fortunately it's on land ownedby a concern with which I have some connection, and I canhave it chopped down without any trouble. Much obliged toyou, Ned. I shan't forget this in a hurry. I'll go rightaway and--"

Tom's further remark was interrupted by the hurriedentrance of Eradicate Sampson. The old man was smiling inpleased anticipation, evidently, at the same time, tryinghard not to give way to too much emotion.

"I's done it, Massa Tom!" he cried exultingly.

"Done what?" asked the young inventor. "I hope you andKoku haven't had another row."

"Come on, Ned," said Tom, after a moment or two of silentcontemplation of Eradicate. "I don't know what this cheerfulcamouflager of mine is talking about, but we'll have to goto see, I suppose. You say you have shut some one up inBoomerang's stable, Rad?"

"Well, sah, Massa Tom, I seen dish yeah Dutchman git aticket-pass offen one ob de reg'lar men. Den he went in deunlucky place an' stayed fo' a long time. When he come out Ijest natchully nabbed him, dat's whut I done, an' I took himto Boomerang's stable."

"How'd you get him to go with you?" asked Ned, for the oldcolored man was feeble, and most of the men employed atTom's plant were of a robust type.

"I done fooled him. I said as how I'd lest brought fromtown in mah mule cart some new sauerkraut, an' he couldsample it if he liked. So he went wif me, an' when I got himto de stable I pushed him in and locked de door!"

"Come on!" cried Tom to his chum. "Rad may be right, afterall, and one of my workmen may be a German spy, though I'vetried to weed them all out.

"However, no matter about that, if he was employed inanother shop, he had no right to go into Number Thirteen.That's a violation of rules. But if he's in Rad's ramshacklestable he can easily get out."

"No, sah, dat's whut he can't do!" insisted thecolored man.

"Why not?" asked Tom.

"'Cause Boomerang's on guard, an' yo'-all knows how datmule of mine can use his heels!"

"I know, Rad," went on Tom; "but this fellow will find away of keeping out of their way. We must hurry."

Followed by the shuffling and chuckling negro, Tom and Nedwent to the rather insecure stable where the mule Boomerangwas kept. That is, the stable was insecure from thestandpoint of a jail. But the sight of the giant Kokumarching up and down in front of the place, armed with a bigclub, reassured Tom.

"Is he in there, Koku?" asked the young inventor.

"Yes, Master! He try once come out, but he approach hishead very close my defense weapon and he go back again."

"We'll have to take a chance. Besides, I don't believe heis, or he'd have fired at Koku. There isn't much to fearwith the giant ready for emergencies. Now we'll see who heis. I can't imagine one of my men turning traitor."

The door was opened and a rather miserable-looking manshuffled out. There was a bloody rag on his head, and heseemed to have made more of an effort to escape than Kokudescribed, for he appeared to have suffered in the ensuingfight.

"Carl Schwen!" exclaimed Tom. "So it was you, was it?"

The German, for such he was, did not answer for a momentHe appeared downcast, and as if suffering. Then a changecame over him. He straightened up, saluted as a soldiermight have done, and a sneering look came into his face. Itwas succeeded by one of pride as the man exclaimed:

"Yes, it is I! And I tried to do what I tried to do forthe Fatherland! I have failed. Now you will have me shot asa spy, I suppose!" he added bitterly.

Tom did not answer directly. He looked keenly at the man,and at last said:

"I am sorry to see this. I knew you were a German, Schwen,but I kept you employed at work that could not, by anypossibility, be considered as used against your country. Youare a good machinist, and I needed you. But if what I hearabout you is true, it is the end."

"It is the end," said the man simply. "I tried and failed.If it had not been for Eradicate--Well, he's smarter than Igave him credit for, that's all!"

The man spoke very good English, with hardly a trace ofGerman accent, but there was no doubt as to his character.

"What will you do with him, Tom?" asked Ned.

"I don't know. I'll have to do a little investigatingfirst. But he must be locked up. Schwen," went on the younginventor, "I'm sorry about this, but I shall have to giveyou into the custody of a United States marshal. You are nota naturalized citizen, are you?"

The man muttered something in German to the effect that hewas not naturalized and was glad of it.

"Then you come under the head of an enemy alien," decidedTom, who understood what was said, "and will have to beinterned. I had hoped to avoid this, but it seems it cannotbe. I am sorry to lose you, but there are more importantmatters. Now let's get at the bottom of this."

Schwen was, after a little delay, taken in charge by theproper officer, and then a search was made of his room, for,in common with some of the other workmen, he lived in aboarding house not far from the plant

There, by a perusal of his papers, enough was revealed toshow Tom the danger he had escaped.

"And yet I don't know that I have altogether escaped it,"he said to Ned, as they talked it over. "There's no tellinghow long this spy work may have been going on. If he hasdiscovered all the secrets of Shop Thirteen it may be a badthing for the Allies and--"

"Look out!" warned Ned, with a laugh. "You'll be sayingthings you don't want to, Tom and not at all in keeping withyour former silence."

"That's so," agreed the young inventor, with a sigh. "Butif things go right I'll not have to keep silent much longer.I may be able to tell you everything."

"Don't tell me--tell Mary," advised his chum. "She feelsyour silence more than I do. I know how such things are."

"I can't tell. The letters are evidently written in code,and I can't translate it offhand. But I'll make anotherattempt at it. And here's one from a person who signshimself Walter Simpson, but the writing is in German."

"Walter Simpson!" cried Ned. "That's my friend of thetree!"

"It is?" cried Tom. "Then things begin to fit themselvestogether. Simpson is a spy, and he was probably trying tocommunicate with Schwen. But the latter didn't get theinformation he wanted, or, if he did get it, he wasn't ableto pass it on to the man in the tree. Eradicate nipped himjust in time."

And, so it seemed, the colored man had done. by accidenthe had discovered that Schwen had prevailed on one of theworkmen in Shop 13 to change passes with him. This enabledthe German spy to gain admittance to the secret place, whichTom thought was so well guarded. The man who let Schwen takethe pass was in the game, too, it appeared, and he was alsoplaced under arrest. But he was a mere tool in the pay ofthe others, and had no chance to gain valuable information.

A hasty search of Shop 13 did not reveal anything missing,and it was surmised (for Schwen would not talk) that he hadnot found time to go about and get all that he was after.

Soon after Schwen's arrest the "Spy Tree," as Tom calledit, was cut down.

"Eradicate certainly did better than I ever expected hewould," declared Tom. "Well, if all goes well, there won'tbe so much need for secrecy after a day or so. We're goingto give her a test, and then--"

"Give who a test?" asked Ned, with a smile.

"You'll soon see," answered Tom, with an answering grin."I hereby invite you and Mr. Damon to come over to ShopThirteen day after to-morrow night and then-- Well, you'llsee what you'll see."

With this Ned had to be content, and he waited anxiouslyfor the appointed time to come.

"I surely will be glad when Tom is more like himself," hemused, as he left his chum. "And i guess Mary will be, too.I wonder if he's going to ask her to the exhibition?"

It developed that Tom had done so, a fact which Nedlearned on the morning of the day set for the test.

"Come over about nine o'clock," Tom said to his chum. "Iguess it will be dark enough then."

Meanwhile Schwen and Otto Kuhn, the other man involved,had been locked up, and all their papers given into thecharge of the United States authorities. A closer guard thanever was kept over No. 13 shop, and some of the workmen,against whom there was a slight suspicion, were transferred.

"Well, we'll see what we shall see," mused Ned on theappointed evening, when a telephone message from Mr. Damoninformed the young bank clerk that the eccentric man wascoming to call for him before going on to the Swift place.

Chapter X

A Runaway Giant

"What do you think it's all about, Mr. Damon?"

"I'm sure I don't know, Ned."

The two were at the home of the young bank clerk,preparing to start for the Swift place, it being nearly nineo'clock on the evening named by the youthful inventor.

"Bless my hat-rack!" went on the eccentric man, "but Tomisn't at all like himself of late. He's working on someinvention, I know that, but it's all I do know. He hasn'tgiven me a hint of it."

"Nor me, nor any of his friends," added Ned. "And he actsso oddly about enlisting--doesn't want even to speak of it.How he got exempted I don't know, but I do know one thing,and that is Tom Swift is for Uncle Sam first, last andalways!"

"It's useless to try to guess what it is Tom is up to. Hehas kept his secret well. The nearest any one has come to itwas when Harry figured out that Tom had a band of giantelephants which he was fitting with coats of steel armor togo against the Germans," observed Ned, when be and Mr. Damonwere on their way.

"Oh, Tom hasn't anything like that!" laughed Ned. "Thatwas only Harry's crazy notion after he saw something big andungainly careening about the enclosed yard of Shop Thirteen.Hello, there go Mary Nestor and her father!" and Ned pointedto the opposite side of the street where the girl and Mr.Nestor could be seen in the light of a street lamp.

"They're going out to see Tom's secret," said Mr. Damon."There's plenty of room in my car. Let's ask them to go withus."

"Surely," agreed Ned, and a moment later he and Mary werein the rear seat while Mr. Damon and Mr. Nestor were in thefront, Mr. Damon at the wheel, and they were soon speedingdown the road.

"I do hope everything will go all right," observed Mary.

"What do you mean?" asked Ned.

"I mean Tom is a little bit anxious about this test."

"Did he tell you what it was to be?"

"No; but when he called to invite father and me to bepresent he seemed worried. I guess it's a big thing, for henever has acted this way before--not talking about hiswork."

"That's right," assented Ned. "But the secret will soon bedisclosed, I fancy. But how is it you aren't going to thedance with Lieutenant Martin? He told me you had halfaccepted for to-night."

"I had." And if it had been light enough Ned would haveseen Mary blushing. "I was going with him. It's a dance forthe benefit of the Red Cross to get money for comfort kitsfor the soldiers. But when Tom sent word that he'd like tohave me present to-night, why--"

"Oh, I see!" broke in Ned, with a little laugh. "'Noughsaid!"

Mary's blushes were deeper, but the kindly night hid them.

Then they conversed on matters connected with the big war--the selling of Liberty Bonds, the Red Cross work and theSurgical Dressings Committee, in which Mary was the head ofa junior league.

"Everybody in Shopton seems to be doing something to helpwin the war," said Mary, and as there was just then a lullin the talk between her father and Mr. Damon her wordssounded clearly.

"Yes, everybody--that is, all but a few," said Mr. Nestor,"and they ought to get busy. There are some young fellows inthis town that ought to be wearing khaki, and I don't meanyou, Ned Newton. You're doing your bit, all right."

"And so is Tom Swift!" exclaimed Mr. Damon, as if therehad been an implied accusation against the young inventor."I heard, only to-day, that one of his inventions--a gashelmet that he planned--is in use on the Western front inEurope. Tom gave his patents to the government, and evenmade a lot of the helmets free to show other factories howto turn them out to advantage."

"He did?" cried Mr. Nestor.

"That's what he did. Talk about doing your bit--"

"I didn't know that," observed Mary's father slowly. "Doyou suppose it's a test of another gas helmet that Tom hasasked us out to see to-night?"

"I hardly think so," said Ned. "He wouldn't wait untilafter dark for that This is something big, and Tom mustintend to have it out in the open. He probably waited untilafter sunset so the neighbors wouldn't come out in flocks.There's been a lot of talk about what is going on in ShopThirteen, especially since the arrest of the German spies,and the least hint that a test is under way would bring outa big crowd."

"I suppose so," agreed Mr. Nestor. "Well, I'm glad to knowthat Tom is doing something for Uncle Sam, even if it's onlyhelping with gas helmets. Those Germans are barbarians, ifever there were any, and we've got to fight them the sameway they fight us! That's the only way to end the war! Nowif I had my way, I'd take every German I could lay my handson--"

"Father, pretzels!" exclaimed Mary.

"Eh? What's that, my dear?"

"I said pretzels!"

"Oh!" and Mr. Nestor's voice lost its sharpness.

"That's my way of quieting father down when he gets toostrenuous in his talk about the war," explained Mary. "Weagreed that whenever he got excited I was to say 'pretzels'to him, and that would make him remember. We made up ourlittle scheme after he got into an argument with a man onthe train and was carried past his station."

"That's right," admitted Mr. Nestor, with a laugh. "Butthat fellow was the most obstinate, pig-headed Dutchman thatever tackled a plate of pig's knuckles and sauerkraut, andif he had the least grain of common sense he'd--"

"Pretzels!" cried Mary.

"Eh? Oh, yes, my dear. I was forgetting again."

There was a moment of merriment, and then, after the talkhad run for a while in other and safer channels, Mr. Damonmade the announcement:

"I think we're about there. We'll be at Tom's place whenwe make the turn and--"

He was interrupted by a low, heavy rumbling.

"What's that?" asked Mr. Nestor.

"It's getting louder--the noise," remarked Mary. "Itsounds as if some big body were approaching down the road--the tramp of many feet. Can it be that troops are marchingaway?"

"Bless my spark plug!" suddenly cried Mr. Damon. "Look!"

They gazed ahead, and there, seen in the glare of theautomobile headlights, was an immense, dark body approachingthem from across a level field. The rumble and roar becamemore pronounced and the ground shook as though from anearthquake.

A glaring light shone out from the ponderous moving body,and above the roar and rattle a voice called:

"And it's running away!" cried Mr. Damon, as he quicklysteered his car to one side--and not a moment too soon! Aninstant later in a cloud of dust, and with a rumble and aroar as of a dozen express trains fused into one, therunaway giant--of what nature they could only guess--flashedand lumbered by, Tom Swift leaning from an opening in thethick' steel side, and shouting something to his friends.

Chapter XI

Tom's Tank

"What was it?" gasped Mary, and, to her surprise, shefound herself close to Ned, clutching his arm.

"I have an idea, but I'd rather let Tom tell you," heanswered.

"But where's it going?" asked Mr. Nestor. "What in theworld does Tom Swift mean by inviting us out here to witnessa test, and then nearly running us down under a Juggernaut?"

"Oh, there must be some mistake, I'm sure," returned hisdaughter. "Tom didn't intend this."

"But, bless my insurance policy, look at that thing go!What in the world is it?" cried Mr. Damon.

The "thing" was certainly going. It had careened from theroad, tilted itself down into a ditch and gone on across thefields, lights shooting from it in eccentric fashion.

"Maybe we'd better take after it," suggested Mr. Nestor."If Tom is--"

"There, it's stopping !" cried Ned. "Come on!"

He sprang from the automobile, helped Mary to get out, andthen the two, followed by Mr. Damon and Mr. Nestor, madetheir way across the fields toward the big object where ithad come to a stop, the rumbling and roaring ceasing.

Before the little party reached the strange machine--the"runaway giant," as they dubbed it in their excitement--abright light flashed from it, a light that illuminated theirpath right up to the monster. And in the glare of this lightthey saw Tom Swift stepping out through a steel door in theside of the affair.

"Are you all right?" he called to his friends, as theyapproached.

"All right, as nearly as we can be when we've been almostscared to death, Tom," said Mr. Nestor.

"I'm surely sorry for what happened," Tom answered, with arelieved laugh. "Part of the steering gear broke and I hadto guide it by operating the two motors alternately. It canbe worked that way, but it takes a little practice to becomeexpert."

"I should say so!" cried Mr. Damon. "But what in the worlddoes it all mean, Tom Swift? You invite us out to seesomething--"

"And there she is!" interrupted the young inventor. "Yousaw her a little before I meant you to, and not underexactly the circumstances I had planned. But there she is!"And he turned as though introducing the metallic monster tohis friends.

"What is she, Tom?" asked Ned. "Name it!"

"My latest invention, or rather the invention of my fatherand myself," answered Tom, and his voice showed the love andreverence he felt for his parent. "Perhaps I should sayadaptation instead of invention," Tom went on, "since thatis what it is. But, at any rate, it's my latest--dad's andmine--and it's the newest, biggest, most improved andpowerful fighting tank that's been turned out of any shop,as far as I can learn.

"Ladies--I mean lady and gentlemen--allow me to present toyou War Tank A, and may she rumble till the pride of theBoche is brought low and humble!" cried Tom.

"Hurray! That's what I say!" cheered Ned.

"That's what I have been at work on lately. I'll give youa little history of it, and then you may come inside andhave a ride home."

"In that?" cried Mr. Damon.

"Yes. I can't promise to move as speedily as your car, butI can make better time than the British tanks. They go aboutsix miles an hour, I understand, and I've got mine geared toten. That's one improvement dad and I have made."

"Ride in that!" cried Mr. Nestor. "Tom, I like you, andI'm glad to see I've been mistaken about you. You have beendoing your bit, after all; but--"

"Oh, I've only begun!" laughed Tom Swift.

"Well, no matter about that. However much I like you,"went on Mr. Nestor, "I'd as soon ride on the wings of athunderbolt as in Tank A, Tom Swift."

"Oh, it isn't as bad as that!" laughed the youngscientist. "But neither is it a limousine. However, comeinside, anyhow, and I'll tell you something about it. ThenI guess we can guide it back. The men are repairing thebreak."

The visitors entered the great craft through the door bywhich Tom had emerged. At first all they saw was a smallcompartment, with walls of heavy steel, some shelves of thesame and a seat which folded up against the wall made oflike powerful material.

"This is supposed to be the captain's room, where he stayswhen he directs matters." Tom explained. "The machinery isbelow and beyond here."

"How'd you come to evolve this?" asked Ned. "I haven'tseen half enough of the outside, to say nothing of theinside."

"You'll have time enough," Tom said. "This is my firstcompleted tank. There are some improvements to be madebefore we send it to the other side to be copied.

"Then they'll make them in England as well as here, andfrom here we'll ship them in sections."

"I don't see how you ever thought of it!" exclaimed thegirl, in wonder.

"Well, I didn't all at once," Tom answered, with a laugh."It came by degrees. I first got the idea when I heard ofthe British tanks.

"When I had read how they went into action and what theyaccomplished against the barbed wire entanglements, and howthey crossed the trenches, I concluded that a bigger tank,one capable of more speed, say ten or twelve miles an hour,and one that could cross bigger excavations--the Englishtanks up to this time can cross a ditch of twelve feet--Ithought that, with one made on such specifications, moreeffective work could be done against the Germans."

"And will yours do that?" asked Ned. "I mean will it doten miles an hour, and straddle over a wider ditch thantwelve feet?"

"It'll do both," promptly answered Tom. "We did a littlebetter than eleven miles an hour a while ago when I yelledto you to get out of the way just now. It's true we weren'tunder good control, but the speed had nothing to do withthat. And as for going over a big ditch, I think westraddled one about fourteen feet across back there, and wecan do better when I get my grippers to working."

"Grippers!" exclaimed Mary.

"What kind of trench slang is that, Tom Swift?" asked Mr.Damon.

"Well, that's a new idea I'm going to try out It'ssomething like this," and while from a distant part of theinterior of Tank A came the sound of hammering, the younginventor rapidly drew a rough pencil sketch.

It showed the tank in outline, much as appear the picturesof tanks already in service--the former simile of two wedge-shaped pieces of metal put together broad end to broad end,still holding good. From one end of the tank, as Tom drewit, there extended two long arms of latticed steelconstruction.

"The idea is," said Tom, "to lay these down in front ofthe tank, by means of cams and levers operated from inside.If we get to a ditch which we can't climb down into and outagain, or bridge with the belt caterpillar wheels, we'll usethe grippers. They'll be laid down, taking a grip on the farside of the trench, and we'll slide across on them."

"And leave them there?" asked Mr. Damon.

"No, we won't leave them. We'll pick them up after we havepassed over them and use them in front again as we needthem. A couple of extra pairs of grippers may be carried foremergencies, but I plan to use the same ones over and overagain."

"I'll be able to show you in a little while," he answered."But it may be enough now if I tell you that the main powerconsists of two big gasolene engines, one on either side.They can be geared to operate together or separately. Andthese engines turn the endless belts made of broad, steelplates, on which the tank travels. The belts pass along theouter edges of the tank longitudinally, and go around coggedwheels at either end of the blunt noses.

"When both belts travel at the same rate of speed the tankgoes in a straight line, though it can be steered from sideto side by means of a trailer wheel in the rear. Making onebelt--one set of caterpillar wheels, you know--go fasterthan the other will make the tank travel to one side or theother, the turn being in the direction of the slowest movingbelt. In this way we can steer when the trailer wheels arebroken."

"Well," answered Tom, "it can do anything any other tankcan do, and then some more. It can demolish a good-sizedhouse or heavy wall, break down big trees, and chew upbarbed-wire fences as if they were toothpicks. I'll show youall that in due time. Just now, if the repairs are finished,we can get back on the road--"

At that moment a door leading into the compartment whereTom and his friends were talking opened, and one of theworkmen said:

"A man outside asking to see you, Mr. Swift."

"Pardon me, but I won't keep you a moment," interrupted asuave voice. "I happened to observe your tank, and I tookthe liberty of entering to see

"Simpson!" cried Ned Newton, as he recognized the man whohad been up the tree. "It's that spy, Simpson, Tom!"

Chapter XII

Bridging a Gap

Such surprise showed both on the face of Ned Newton andthat of the man who called himself Walter Simpson that itwould be hard to say which was in the greater degree. For amoment the newcomer stood as if he had received all electricshock, and was incapable of motion. Then, as the echoes ofNed's voice died away and the young bank clerk, being thefirst to recover from the shock, made a motion toward theunwelcome and uninvited intruder, Simpson exclaimed.

"I will not bother now. Some other time will do as well."

Then, with a haste that could be called nothing less thanprecipitate, he made a turn and fairly shot out of the doorby which he had entered the tank.

Tom Swift was not one to let a friend rush alone into whatmight be danger. He realized immediately what his chum meantwhen he called out the identity of the intruder, and,wishing to clear up some of the mystery of which he becameaware when Schwen was arrested and the paper showing acorrespondence with this Simpson were found, Tom darted outto try to assist in the capture.

"He went this way!" cried Ned, who was visible in theglare of the searchlight that still played its powerfulbeams over the stern of the tank, if such an ungainlymachine can be said to have a bow and stern. "Over thisway!"

"I'm with you!" cried Tom. "See if you can pick up thatman who just ran out of here!" he cried to the operator ofthe searchlight in the elevated observation section of whatcorresponded to the conning tower of a submarine. This was asort of lookout box on top of the tank, containing, amongother machines, the searchlight. "Pick him up!" cried Tom.

The operator flashed the intense white beam, like a fingerof light, around in eccentric circles. but though thisbrought into vivid relief the configuration of the field androad near which the tank was stalled, it showed no runningfugitive. Tom and Ned were observed--shadows of black in theglare--by Mary and her friends in the tank, but there was noone else.

"Come on!" cried Ned. "We can find him, Tom!"

But this was easier said than done. Even though they wereaided by the bright light, they caught no glimpse of the manwho called himself Simpson.

"Guess he got away," said Tom, when he and Ned had circledabout and investigated many clumps of bushes, trees, stumpsand other barriers that might conceal the fugitive.

"Hardly that," and Tom smiled. "Though if all goes wellthe men who operate this tank later may be searching for menin real shell holes."

"Is this one going to the other side?" asked Ned, as thetwo walked back toward the tank.

"I hope it will be the first of my new machines on theWestern front," Tom answered. "But I've still got to perfectit in some details and then take it apart. After that, if itcomes up to expectations, we'll begin making them inquantities."

"Did you get him?" asked Mr. Damon eagerly, as the twoyoung men came back to join Mary and her friends.

"No, he got away," Tom answered.

"Did he try to blow up the tank?" asked Mr. Nestor, whohad an abnormal fear of explosives. "Was he a German spy?"

"Hardly, I guess," answered the young inventor. "He didn'thave a chance to do that. Anyhow we won't remain here long.Now, Ned, what about this chap? Is he really the one you sawup in the tree?"

"I not only saw him but I felt him," answered Ned, with arueful look at his fingers. "He stepped right on me. Andwhen he came inside the tank to-night I knew him at once. Iguess he was as surprised to see me as I was to see him."

"But what was his object?" asked Mr. Nestor.

"He must have some connection with my old enemy,Blakeson," answered Tom, "and we know he's mixed up withSchwen. From the looks of him I should say that thisSimpson, as he calls himself, is the directing head of thewhole business. He looks to be the moneyed man, and thebrains of the plotters. Blakeson is smart, in a mechanicalway, and Schwen is one of the best machinists I've everemployed. But this Simpson strikes me as being the slick oneof the trio."

"But what made him come here, and what did he want?" askedMary. "Dear me! it's like one of those moving picture plots,only I never saw one with a tank in it before--I mean a tanklike yours, Tom."

"Yes, it is a bit like moving picture--especially chasingSimpson by searchlight," agreed the young inventor. "As towhat he wanted, I suppose he came to spy out some of mysecret inventions--dad's and mine. He's probably been hidingand sneaking around the works ever since we arrested Schwen.Some of my men have reported seeing strangers about, but Ihave kept Shop Thirteen well guarded.

"However, this fellow may have been waiting outside, andhe may have followed the tank when we started off a littlewhile ago for the night test. Then, when he saw our mishapand noticed that we were stalled, he came in, boldly enough,thinking, I suppose, that, as I had never seen him, he wouldtake a chance on getting as much information as he could ina hurry."

"But he didn't count on Ned's being here!" chuckled Mr.Damon.

"No; that's where he slipped a cog," remarked Mr. Nestor."Well, Tom, I like your tank, what I've seen of her, butit's getting late and I think Mary and I had better begetting back home."

"We'll be ready to start in a little while," Tom said,after a brief consultation with one of his men. "Still,perhaps it would be just as well if you didn't ride backwith me. She may go all right, and then, again, she may not.And as it's dark, and we're in a rough part of the field,you might be a bit shaken up. Not that the tank minds it!"the young inventor hastened to add "She's got to do her bitover worse places than this--much worse--but I want to gether in a little better working shape first. So if you don'tmind, Mary, I'll postpone your initial trip."

"Oh, I don't mind, Tom! I'm so glad you've made this! Iwant to see the war ended, and I think machines like thiswill help."

"Well, I'm coming over to-morrow to have a look at it bydaylight," said Mr. Damon, as he started toward his car.

"So am I," added Mary. "Please call for me, Mr. Damon."

"I will," he promised.

Mr. Nestor, his daughter, and Mr. Damon went back to theautomobile, while Ned remained with Tom. In a little whilethose in the car heard once more the rumbling and roaringsound and felt the earth tremble. Then, with a flashing oflights, the big, ungainly shape of the tank lifted herselfout of the little ditch in which she had come to a halt, andbegan to climb back to the road.

Ned Newton stood beside Tom in the control tower of thegreat tank as she started on her homeward way.

"Isn't it wonderful!" murmured Mary, as she saw Tank Alumbering along toward the road. "Oh, and to think thathuman beings made that To think that Tom should know how tobuild such a wonderful machine!"

"And run it, too, Mary! That's the point! Make it run!"cried her father. "I tell you, that Tom Swift is a wonder!"

"Bless my dictionary, he sure is!" agreed Mr. Damon.

Along the road, back toward the shop whence it hademerged, rumbled the tank. The noise brought to their doorsinhabitants along the country thoroughfare, and some of themwere frightened when they saw Tom Swift's latest warmachine, the details of which they could only guess at inthe darkness.

"She'll butt over a house if it gets in her path, knockdown trees, chew up barbed-wire, and climb down into ravinesand out again, and go over a good-sized stream without awhimper," said Tom, as he steered the great machine.

There was little chance then for Ned to see much of theinside mechanism of the tank. He observed that Tom, standingin the forward tower, steered it very easily by a smallwheel or by a lever, alternately, and that he communicatedwith the engine room by means of electric signals.

"And she steers by electricity, too," Tom told his friend."That was one difficulty with the first tanks. They had tobe steered by brute force, so to speak, and it was aterrific strain on the man in the tower. Now I can guidethis in two ways: by the electric mechanism which swings thetrailer wheels to either side, or by varying the speed ofthe two motors that work the caterpillar belts. So if onebreaks down, I have the other."

"Got any guns aboard her--I mean machine guns?" asked Ned.

"Not yet. But I'm going to install some. I wanted to getthe tank in proper working order first. The guns are onlyincidental, though of course they're vitally necessary whenshe goes into action. I've got 'em all ready to put in. Butfirst I'm going to try the grippers."

And they did. Ned was greatly shaken up, and fairly tossedfrom side to side of the steering tower. For the tankcontained no springs, except such as were installed aroundthe most delicate machinery, and it was like riding in adump cart over a very rough road.

"However, that's part of the game," Tom observed.

Tank A reached her "harbor" safely--in other words, themachine shop enclosed by the high fence, inside of which shehad been built.

Tom and Ned made some inquiries of Koku and Eradicate asto whether or not there had been any unusual sights orsounds about the place. They feared Simpson might have cometo the shop to try to get possession of important drawingsor data.

But all had been quiet, Koku reported Nor had Eradicateseen or heard anything out of the ordinary.

"I will," promised the young bank clerk. "I want to seemore of what makes the wheels go round." And he laughed athis own ingenuousness.

The next day Tom showed his friends as much as they caredto see about the workings of the tank. They inspected thepowerful gasolene engines, saw how they worked the endlessbelts made of plates of jointed steel, which, running oversprocket wheels, really gave the tank its power by providinggreat tractive force.

Any self-propelled vehicle depends for its power, eitherto move itself or to push or to pull, on its tractive force--that is, the grip it can get on the ground.

In the case of a bicycle little tractive power is needed,and this is provided by the rubber tires, which grip theground. A locomotive depends for its tractive power on itsweight pressing on its driving wheels, and the more drivingwheels there are and the heavier the locomotive, the more itcan pull, though in that case speed is lost. This is whyfreight locomotives are so heavy and have so many largedriving wheels. They pull the engine along, and the carsalso, by their weight pressing on the rails.

The endless steel belts of a tank are, the same as thewheels of a locomotive. And the belts, being very broad,which gives them a large surface with which to press on theground, and the tank being very heavy, great power toadvance is thus obtained, though at the sacrifice of speed.However, Tom Swift had made his tank so that it would doabout ten miles and more an hour, nearly double the progressobtained up to that time by the British machines.

His visitors saw the great motors, they inspected thecompact but not very attractive living quarters of the crew,for provision had to be made for the men to stay in the tankif, perchance, it became stalled in No Man's Land,surrounded by the enemy.

The tank was powerfully armored and would be armed. Therewere a number of machine guns to be installed, quick-firersof various types, and in addition the tank could carry anumber of riflemen.

It was upon the crushing power of the tank, though, thatmost reliance was placed. Thus it could lead the way for aninfantry advance through the enemy's lines, making nothingof barbed wire that would take an artillery fire of severaldays to cut to pieces.

"And now, Ned," said Tom, about a week after the nighttest of the tank, "I'm going to try what she'll do inbridging a gap."

"Have you got her in shape again?"

"Yes, everything is all right. I've taken out the weakpart in the steering gear that nearly caused us to run youdown, and we're safe in that respect now. And I've got thegrippers made. It only remains to see whether they're strongenough to bear the weight of my little baby," and Tomaffectionately patted the steel sides of Tank A.

While his men were getting the machine ready for a testout on the road, and for a journey across a small stream notfar away, Torn told his chum about conceiving the idea forthe tank and carrying it out secretly with the aid of hisfather and certain workmen.

"That's the reason the government exempted me fromenlisting," Tom said. "They wanted me to finish this tank. Ididn't exactly want to, but I considered it my 'bit.' Afterthis I'm going into the army, Ned."

"Glad to hear it, old man. Maybe by that time I'll havethis Liberty Bond work finished, and I'll go with you. We'llhave great times together! Have you heard anything more ofSimpson, Blakeson and Scoundrels?" And Ned laughed as henamed this "firm."

"No," answered Tom. "I guess we scared off that slickGerman spy."

Once more the tank lumbered out along the road. It was amighty engine of war, and inside her rode Tom and Ned. Maryand her father had been invited, but the girl could notquite get her courage to the point of accepting, nor did Mr.Nestor care to go. Mr. Damon, however, as might be guessed,was there.

"Bless my monkey wrench, Tom!" cried the eccentric man, ashe noted their advance over some rough ground, "are youreally going to make this machine cross Tinkle Creek on abridge of steel you carry with you?"

"I'm going to try, Mr. Damon."

A little later, after a successful test up and down asmall gully, Tank A arrived at the edge of Tinkle Creek, asmall stream about twenty feet wide, not far from Tom'shome. At the point selected for the test the banks were highand steep.

"If she bridges that gap she'll do anything," murmuredNed, as the tank came to a stop on the edge.

Chapter XIII

Into a Trench

Tom cast a hasty glance over the mechanism of the machinebefore he started to cross the stream by the additional aidof the grippers, or spanners, as he sometimes called thislatest device.

Along each side, in a row of sockets, were two longgirders of steel, latticed like the main supports of abridge. They were of peculiar triangular construction,designed to support heavy weights, and each end was broadlyflanged to prevent its sinking too deeply into the earth oneither side of a gully or a stream.

The grippers also had a sort of clawlike arrangement oneither end, working on the principle of an "orange-peel"shovel, and these claws were designed to grip the earth toprevent slipping.

The spanners would be pulled out from their sockets on theside of the tank by means of steel cables, which wereoperated from within. They would be run out across the gapand fastened in place. The tank was designed to travel alongthem to the other side of the gap, and, once there. to picktip the girders, slip them back into place on the sides, andthe engine of war would travel on.

"You are mightily excited, Tom.

"I admit it, Ned. You see, I have not tried the grippersout except on a small model. They worked there, but whetherthey will work in practice remains to be seen. Of course, atthis stage, I'm willing to stake my all on the results. butthere is always a half-question until the final try-outunder practical conditions."

"Well, we'll soon see," said one of the workmen. "Are youready, Mr. Swift?"

"All ready," answered Tom.

Tank A, as she was officially known, had come to a stop,as has been said, on the very edge of Tinkle Creek. Thebanks were fairly solid here, and descended precipitously tothe water ten feet below. The shores were about twenty feetapart.

"I don't like to suppose anything of the sort. But if theydo, we're going down!"

"Can you get up again?"

"That remains to be seen," was the non-committal reply."Well, here goes, anyhow!"

Going up into the observation tower, which was onlyslightly raised above the roof of the highest part of thetank, Tom gave the signal for the motors to start. There wasa trembling throughout the whole of the vast structure. Tomthrew back a lever and Ned, peering from a side observationslot, beheld a strange sight.

Like the main arm of some great steam shovel, two long,latticed girders of steel shot out from the sides of thetank. They gave a half turn, as they were pulled forward bythe steel ropes, so that they lay with their broadersurfaces uppermost.

Straight across the stream they were pulled, theirclawlike ends coming to a rest on the opposite bank. Thenthey were tightened into place by a backward pull on theoperating cables, and Tom, with a sigh of relief, announced:

"Well, so far so good!"

"Do we go over now?" inquired Ned.

"Over the top--yes, I hope," answered Tom, with a laugh."How about you down there?" he called to the engine roomthrough a telephone which could only be used when themachinery was not in action, there being too much noise topermit the use of any but visual signals after that.

"All right," came back the answer. "We're ready when youare."

"Then here we go!" said Tom. "Hold fast, Ned! Of coursethere's no real telling what will happen, though I believewe'll come out of it alive."

"Cheerful prospect," murmured Ned.

The grippers were now in place. It only remained for thetank to propel herself over them, pick them up on the otherside of Tinkle Creek, and proceed on her course.

Tom Swift hesitated a moment, one hand on the startinglever and the other on the steering wheel. Then, with aglance at Ned, half whimsical and half resolute, Tom startedTank A on what might prove to be her last journey.

Slowly the ponderous caterpillar belts moved around on thesprocket wheels. They ground with a clash of steel on thesurface of the spanners. So long was the tank that theforward end, or the "nose," was halfway across the streambefore the bottom part of the endless belts gripped thelatticed bridge.

"If we fall, we'll span the creek, not fall into it,"murmured Ned, as he looked from the observation slot.

"That's what I counted on," Tom said. "We'll get out, evenif we do fall."

But Tank A was not destined to fall. In another moment herentire weight rested on the novel and transportable bridgeTom Swift had evolved. Then, as the gripping ends of thegirders sank farther into the soil, the tank went on herway.

Slowly, at half speed, she crawled over the steel beams,making progress over the creek and as safely above the wateras though on a regularly constructed bridge.

On and on she went. Now her entire weight was over themiddle of the temporary structures. If they were going togive way at all, it would be at this point But they did notgive. The latticed and triangular steel, than which there isno stronger form of construction, held up the immenseweight of Tank A, and on this novel bridge she propelledherself across Tinkle Creek.

"Well, the worst is over," remarked Ned, as he saw thenose of the tank project beyond the farthermost bank.

"Yes, even if they collapse now nothing much can happen,"Tom answered. "It won't be any worse than wallowing downinto a trench and out again. But I think the spanners willhold."

And hold they did! They held, giving way not a fraction ofan inch, until the tank was safely across, and then, after alittle delay, due to a jamming of one of the recoverycables, the spanners were picked up, slid into the receivingsockets, and the great war engine was ready to proceedagain.

"Hurrah!" cried Ned. "She did it, Tom, old man!" and heclapped his chum resoundingly on the back.

"Bless my apple pie!" cried Mr. Damon, who was as muchpleased as either of the boys, "this is what I call great!"

"Yes, she did all that I could have hoped for," said Tom."Now for the next test."

"Bless my collar button! is there another?"

"Just down into a trench and out again." Tom said. "Thisis comparatively simple. It's only what she'll have to doevery day in Flanders."

The tank waddled on. A duck's sidewise walk is about theonly kind of motion that can be compared to it. The goingwas easier now, for it was across a big field, and Tom toldhis friends that at the other end was a deep, steep androcky ravine in which he had decided to give the tankanother test.

"We'll imagine that ravine is a trench," he said, "andthat we've got to get on the other side of it. Of course, wewon't be under fire, as the tanks will be at the front, butaside from that the test will be just as severe."

A little later Tank A brought her occupants to the edge ofthe "trench."

"Now, little girl," cried Tom exultingly, patting therough steel side of his tank, "show them what you can do!"

He steered the machine straight for the edge of theravine, and as the nose slipped over and the broad steelbelts bit into the earth the tank tilted downward at asickening angle.

She appeared to be making the descent safely, when therewas a sudden change. The earth seemed to slip out from underthe broad caterpillar belts, and then the tank moved morerapidly.

"Tom, we're turning over!" shouted Ned. "We're capsizing!"

Chapter XIV

The Ruined Factory

Only too true were the words Ned Newton shouted to hischum. Tank A was really capsizing. She had advanced to theedge of the gully and started down it, moving slowly on thecaterpillar bands of steel. Then had come a sudden lurch,caused, as they learned afterward, by the slipping off of agreat quantity of shale from an underlying shelf of rock.

This made unstable footing for the tank. One side sanklower than the other, and before Tom could neutralize thisby speeding up one motor and slowing down the other the tankslowly turned over on its side.

"But she isn't going to stop here!" cried Ned, as he foundhimself thrown about like a pill in a box. "We're going allthe way over!"

"Let her go over!" cried Tom, not that he could stop thetank now. "It won't hurt her. She's built for lust this sortof thing!"

And over Tank A did go. Over and over she rolled,sidewise, tumbling and sliding down the shale sides of thegreat gully.

"Hold fast! Grab the rings!" cried Tom to his twocompanions in the tower with him. "That's what they're for!"

Ned and Mr. Damon understood. In fact, the latter hadalready done as Tom suggested. The young inventor had readthat the British tanks frequently turned turtle, and he hadthis in mind when he made provision in his own for thesafety of passengers and crew.

As soon as he felt the tank careening, Tom had pressed thesignal ordering the motors stopped, and now only the forceof gravity was operating. But that was sufficient to carrythe big machine to the bottom of the gulch, whither she slidwith a great cloud of sand, shale and dust.

"Bless my--bless my--" Mr. Damon was murmuring, but he wasso flopped about, tossed from one side to the other, and ittook so much of his attention and strength to hold on to thesafety ring, that he could not properly give vent; to one ofhis favorite expressions.

But there comes an end to all things, even to the descentof a tank, and Tom's big machine soon stopped rolling,sliding, and turning improvised somersaults, and rested in apile of soft shale at the bottom of the gully. And thetank was resting on her back!

"We've turned turtle!" cried Ned, as he noted that he wasstanding on what, before, had been the ceiling of theobservation tower. But as everything was of steel, and asthere was no movable furniture, no great harm was done. Infact, one could as well walk on the ceiling of the tank ason the floor.

"But how are you going to get her right side up?" askedMr. Damon.

"Oh, turning upside down is only one of the stunts of thegame. I can right her," was the answer.

"How?" asked Ned.

"Well, she'll right herself if there's ground enough forthe steel belts to get a grip on.

"But can the motors work upside down?"

"They surely can!" responded Tom. "I made 'em that way onpurpose. The gasolene feeds by air pressure, and that worksstanding on its head, as well as any other way. It's goingto be a bit awkward for the men to operate the controls, butwe won't be this way long. Before I start to right her.though, I want to make sure nothing is broken."

Tom signaled to the engine room, and, as the power was offand the speaking tube could be used, he called through it:

"How are you down there?"

"Right-o!" came back the answer from a little EnglishmanTom had hired because he knew something about the Britishtanks. "'Twas a bit of nastiness for a while, but it won'ttake us long to get up ag'in."

"That's good!" commented Tom. "I'll come down and have alook at you."

It was no easy matter, with the tank capsized, to get tothe main engine room, but Tom Swift managed it. To hisdelight, aside from a small break in one of the minormachines, which would not interfere with the operation ormotive force of the monster war engine, everything was ingood shape. There was no leak from the gasolene tanks, whichwas one of the contingencies Tom feared, and, as he hadsaid, the motors would work upside down as well as rightside up, a fact he had proved more than once in his Hawk.

"Well, we'll make a start," he told his chief engineer."Stand by when I give the signal, and we'll try to crawl outof this right side up."

"How are you going to do it?" asked Ned, as his chumcrawled back into the observation tower.

"Well, I'm going to run her part way up the very steepestpart of the ravine I can find--the side of a house would doas well if it could stand the strain. I'm going to stand thetank right up on her nose, so to speak, and tip her over soshe'll come right again."

Slowly the tank started off, while Tom and his friends inthe observation tower anxiously awaited the result of thenovel progress. Ned and Mr. Damon clung to the safety rings.Tom put his arm through one and hung on grimly, while heused both hands on the steering apparatus and the controls.

Of course the trailer wheels were useless in a case ofthis kind, and the tank had to be guided by the two beltsrun at varying speeds.

"Here we go!" cried Tom, and the tank started. It was aqueer sensation to be moving upside down, but it did notlast very long. Tom steered the tank straight at theopposite wail of the ravine, where it rose steeply. One ofthe broad belts ran up on that side. The other was revolvedin the opposite direction. Up and up, at a sickening angle,went Tank A.

Slowly the tank careened, turning completely over on herlonger axis, until, as Tom shut off the power, he and hisfriends once more found themselves standing where theybelonged--on the floor of the observation tower.

"Right side up with care!" quoted Ned, with a laugh. "Well,that was some stunt--believe me!"

"Bless my corn plaster, I should say so!" cried Mr. Damon.

"Well, I'm glad it happened," commented Tom. "It showedwhat she can do when she's put to it. Now we'll get out ofthis ditch."

Slowly the tank lumbered along, proper side up now, themen in the motor room reporting that everything was allright, and that with the exception of a slight unimportantbreak, no damage had been done.

Straight for the opposite steep side of the gully Tomdirected his strange craft, and at a point where the wall ofthe gulch gave a good footing for the steel belts, Tank Apulled herself out and up to level ground.

"Well, I'm glad that's over," remarked Ned, with a sigh ofrelief, as the tank waddled along a straight stretch. "Andto think of having to do that same thing under heavy fire !"

"That's part of the game," remarked Tom. "And don't forgetthat we can fire, too--or we'll be able to when I get theguns in place. They'll help to balance the machine better,too, and render her less likely to overturn."

Tom considered the test a satisfactory one and, a littlelater, guided his tank back to the shop, where men were setto work repairing the little damage done and making someadjustments.

"What's next on the program?" asked Ned of his chum oneday about a week later. "Any more tests in view?"

"Yes," answered Tom. "I've got the machine guns in placenow. We are going to try them out and also endeavor todemolish a building and some barbed wire. Like to comealong?"

"I would!" cried Ned.

A little later the tank was making her way over a field.Tom pointed toward a deserted factory, which had long beenpartly in ruins, but some of the walls of which still stood.

"I'm going to bombard that," he announced, and then try tobatter it down and roll over it like a Juggernaut. Are yougame?"

Slowly, but with resistless energy, the tank approachedthe ruined factory.

"Are you sure there's no one in it, Tom?"

"Sure! Blaze away!"

Chapter XV

Across Country

Ned Newton sighted his machine gun. Tom had showed him howto work it, and indeed the young bank clerk had had somepractice with a weapon like this, erected on a stationarytripod. But this was the first time Ned had attempted tofire from the tank while it was moving, and he found it analtogether different matter.

"Say, it sure is hard to aim where you want to!" heshouted across to Tom, it being necessary, even in theconning tower, where this one gun was mounted, to speakloudly to make one's self heard above the hum, the roar andrattle of the machinery in the interior of Tank A, andbelow and to the rear of the two young men.

"Well, that's part of the game," Tom answered. "I'msending her along over as smooth ground as I can pick out,but it's rough at best. Still this is nothing to what you'llget in Flanders."

"If I get there!" exclaimed Ned grimly. "Well, here goes!"and once more he tried to aim the machine gun at the middleof the brick wall of the ruined factory.

A moment later there was a rattle and a roar as the quick-firing mechanism started, and a veritable hail of bulletsswept out at the masonry. Tom and Ned could see where theystruck, knocking off bits of stone, brick and cement

"Sweep it, Ned! Sweep it!" cried Tom. "Imagine a crowd ofGermans are charging out at you, and sweep 'em out of theway!"

Obeying this command, the young man moved the barrel ofthe machine gun from side to side and slightly up and down.The effect was at once apparent. The wall showed spatter-marks of the bullets over a wider area, and had a body ofTeutons been before the factory, or even inside it, many ofthem would have been accounted for, since there were severalholes in the wall through which Ned's bullets sped, carryingpotential death with them.

"That's better!" shouted Tom. "That'll do the business!Now I'm going to open her up, Ned!"

"Open her up?" cried the young bank clerk, as he ceasedfiring.

"Yes; crack the wall of that factory as I would a nut!Watch me take it on high--that is, if the old tank doesn'tgo back on me!"

"You mean you're going to ride right over that building,Tom ?"

"I mean I'm going to try! If Tank A does as I expect herto, she'll butt into that wall, crush it down by force andweight, and then waddle over the ruins. Watch!"

Tom sent some signals to the motor room. At once there wasnoticed an increase in the vibrations of the ponderousmachine.

"They're giving her more speed," said Tom. "And I guesswe'll need it."

Straight for the old factory went Tank A. In spite of itsruined condition, some of the walls were still firm, andseemed to offer a big obstacle to even so powerful an engineof war as this monstrous tank.

"Get ready now, Ned," Tom advised. "And when I crack heropen for you cut loose with the machine gun again. This gunis supposed to fire straight ahead and a little to eitherside. There are other guns at left and right, amidships, asI might say, and there's also one in the stern, to take careof any attack from that direction.

"The men in charge of them will fire at the same time youdo, and it will be as near like a real attack as we can makeit--with the exception of not being fired back at. And Iwouldn't mind if such were the case, for I don't believeanything, outside of heavy artillery, will have any effecton this tank."

Tank A was now almost at her maximum speed as sheapproached closer to the deserted factory. Ned and Tom, inthe conning tower, saw the largest of the remaining wallslooming before them. Straight at it rushed the ponderousmachine, and the next moment there came a shock which almostthrew Ned away from his gun and back against the steel wallbehind him.

"Hold fast!" cried Tom. "Here we go! Fire. Ned! Fire!"

There was a crash as the blunt nose of the great war tankhit the wall and crumpled it up.

A great hole was made in the masonry, and what was notcrushed under the caterpillar belts of the tank fell in ashower of bricks, stone and cement on top of the machine.

Like a great hail storm the broken masonry pelted thesteel sides and top of the tank. But she felt them no morethan does an alligator the attacks of a colony of ants.Right on through the dust the tank crushed her way. Added tothe noise of the falling walls was that of the machine guns,which were barking away like a kennel of angry hounds eagerto be unleashed at the quarry.

Ned kept his gun going until the heat of it warned him tostop and let the barrel cool, or he knew he would jam someof the mechanism. The other guns were firing, too, and thebullets sent up little spatter points of dust as they hit.

"Yes, she's just chewing it up, all right!" cried theyoung inventor, his eyes shining with delight.

The tank had actually burst her way through the solid wallof the old factory, permission to complete the demolition ofwhich Tom had secured from the owners. Then the greatmachine kept right on. She fairly "walked" over the piles ofmasonry, dipped down into what had been a basement, nowpartly filled with debris, and kept on toward another wall.

"I'm going through that, too!" cried Tom.

And he did, knocking it down and sending his tank over thepiled-up ruins, while the machine guns barked, coughed andspluttered, as Ned and the others inside the tank held backthe firing levers.

Right through the opposite wall, as through the one shehad already demolished, the tank careened on her way, toemerge, rather battered and dust-covered, on the other sideof what was left of the factory. And there was not much ofit left. Tank A had well-nigh completed its demolition.

"If there'd been a nest of Germans in there," said Tom, ashe brought the machine to a stop in a field beyond thefactory, "they'd have gotten out in a hurry."

"Or taken the consequences," added Ned, as he wiped thesweat from his powder-blackened and oil-smeared face. "Icertainly kept my gun going."

"Yes, and so did the others," reported one of themechanics, as he emerged from the "cubby hole," where thegreat motors had now ceased their hum and roar.

"How'd she stand it?" asked Tom.

"All right inside," answered the man. "I was wondering howshe looks from the outside."

"Oh, it would take more than that to damage her," saidTom, with pardonable pride. "That was pie for her! Solidconcrete, which she may have to chew up on the Westernfront, may present another kind of problem, but I guessshe'll be able to master that too. Well, let's have a look."

He and Ned, with some of the crew and gunners, wentoutside the tank. She was a sorry-looking sight, verydifferent from the trim appearance she had presented whenshe first left the shop. Bricks, bits of stone, and piles ofbroken cement in chunks and dust lay thick on her broadback. But no real damage had been done, as a hastyexamination showed.

"Well, are you satisfied, Tom?" asked his chum.

"Yes, and more," was the answer. "Of course this wasn'tthe hardest test to which she could have been submitted, butit will do to show what punishment she can stand. Being shotat from big guns is another matter. I'll have to wait untilshe gets to Flanders to see what effect that will have. ButI know the kind of armor skin she has, and that doesn'tworry me. There's one thing more I want to do while I haveher out now."

"What's that?" asked Ned.

"Take her for a long trip cross country, and then shoveher through some extra heavy barbed wire. I'm certain she'llchew that up, but I want to see it actually done. So now, ifyou want to come along, Ned, we'll go cross country."

"I'm with you!"

"Get inside then. We'll let the dust and masonry blow andrattle off as we go along."

The tank started off across the fields, which stretchedfor many miles on either side of the deserted factory, whensuddenly Ned, who was again at his post in the observationtower, called:

"Look, Tom!"

"What at?"

"That corner of the factory which is still standing. Lookat those men coming out and running away!"

Ned pointed, and his chum, leaning over from the steeringwheel and controls, gave a start of surprise as he saw threefigures clambering down over the broken debris and makingtheir way out of what had once been a doorway.

"Did they come out of the factory, Ned?"

"They surely did! And unless I miss my guess they were init, or around it, when we went through like a fellowcarrying the football over the line for a touchdown."

"In there when the tank broke open things?"

"I think so. I didn't see them before, but they certainlyran out as we started away."

"This has got to be looked into!" decided Tom. "Come on,Ned! It may be more of that spy business !"

Tom Swift stopped the tank and prepared to get out

Chapter XVI

The Old Barn

"There's no use chasing after 'em, Tom," observed Ned, asthe two chums stood side by side outside the tank and gazedafter the three men running off across the fields as fast asthey could go. "They've got too much a start of us."

"I guess you're right, Ned," agreed Tom. "And we can'tvery well pursue them in the tank. She goes a bit fasterthan anything of her build, but a running man is more than amatch for her in a short distance. If I had the Hawk here,there'd be a different story to tell."

"Well, seeing that you haven't," replied Ned, suppose welet them go--which we'll have to, whether we want to or not--and see where they, were hiding and if they left any tracesbehind."

"That's a good idea," returned Tom.

The place whence the men had emerged was a portion of theold factory farthest removed from the walls the tank hadcrunched its way through. Consequently, that part was theleast damaged.

Tom and Ned came to what seemed to have been the office ofthe building when the factory was in operation. A door, fromwhich most of the glass had been broken, hung on one hinge,and, pushing this open, the two chums found themselves in aroom that bore evidences of having been the bookkeeper'sdepartment. There were the remains of cabinet files, and abroken letter press, while in one corner stood a safe.

"Maybe they were cracking that," said Ned.

"They were wasting their time if they were," observed Tom,"for the combination is broken--any one can open it," and hedemonstrated this by swinging back one of the heavy doors.

A quantity of papers fell out, or what had been papers,for they were now torn and the edges charred, as if by somerecent fire.

"They were burning these!" cried Ned. "You can smell thesmoke yet. They came here to destroy some papers, and wesurprised them!"

"I believe you're right," agreed Tom. "The ashes are stillwarm." And he tested them with his hand. "They wanted todestroy something, and when they found we were here theyclapped the blazing stuff into the safe, thinking it wouldburn there.

"But the closing of the doors cut off the supply of airand the fire smouldered and went out. It burned enough sothat it didn't leave us very much in the way of evidence,though," went on Tom ruefully, as he poked among the charredscraps.

"Maybe you can read some of 'em," suggested Ned.

"Part of the writing is in German," Tom said, as he lookedover the mass. "I don't believe it would be worth while totry it. Still, I can save it. Here, I'll sweep the stuffinto a box, and if we get a chance we can try to patch ittogether," and finding a broken box in what had been thefactory office the young inventor managed to get into it thecharred remains of the papers.

A further search failed to reveal anything that would beuseful in the way of evidence to determine what object thethree men could have had in hiding in the ruins, and Tom andNed returned to the tank.

"What do you think about them, Tom?" asked Ned, as theywere about to start off once more for the cross-countrytest.

"Well, it seems like a silly thing to say--as if Iimagined my tank was all there was in this part of thecountry to make trouble--but I believe those men had someconnection with Simpson and with that spy Schwen!"

"I agree with you!" exclaimed Ned. "And I think if wecould get head or tail of those burned papers we'd find thatthere was some correspondence there between the man I saw upthe tree and the workman you had arrested."

"Too bad we weren't a bit quicker," commented Tom. "Theymust have been in the factory when we charged it--probablycame there to be in seclusion while they talked, plotted andplanned. They must have been afraid to go out when the tankwas walking through the walls."

"No, I didn't see 'em as soon as you did, and when theywere running they had their backs toward me. Was Simpsonone?"

"I can't be sure. If one was, I guess he'll think we arekeeping pretty closely after him, and he may give this partof the country a wide berth."

"I hope he does," returned Tom. "Do you know, Ned, I havean idea that these fellows--Schwen Simpson, and those backof them, including Blakeson--are trying to get hold of thesecret of my tank for the Germans."

"I shouldn't be surprised. But you've got it finished now,haven't you? They can't get your patents away from you."

"No, it isn't that," said Tom. "There are certain secretsabout the mechanism of the tank--the way I've increased thespeed and power, the use of the spanners, and things likethat--which would be useful for the Germans to know. Iwouldn't want them to find out these secrets, and they coulddo that if they were in the tank a while, or had her intheir possession."

"They couldn't do that, Tom--get possession of her--couldthey?"

"There's no telling. I'm going to be doubly on the watch.That fellow Blakeson is in the pay of the plotters, Ibelieve. He has a big machine shop, and he might try toduplicate my tank if he knew how she was made inside."

"I see! That's why he was inquiring about a goodmachinist, I suppose, though he'll be mightily surprisedwhen he learns it was you he was talking to the time yourHawk met with the little mishap."

"Yes, I guess maybe he will be a bit startled," agreedTom. "But I haven't seen him around lately, and maybe he hasgiven up."

"Don't trust to that!" warned Ned.

The tank was now progressing easily along over fields,hesitating not at small or big ditches, flow going uphilland now down, across a stretch of country thinly settled,where even fences were a rarity. When they came to woodenones Tom had the workmen get out and take down the bars. Ofcourse the tank could have crushed them like toothpicks, butTom was mindful of the rights of farmers, and a broken fence